Eye color genes may help forensic investigations

LONDON (Reuters Life!) - Scientists have identified three new genes that determine subtle variations in human eye color -- clues that could help forensic investigators using DNA left at a crime scene to track down criminal suspects.

Researchers from the Erasmus University Medical Center Rotterdam in the Netherlands used a technique called a genome-wide association study, which scans gene maps, to analyze the eye color of about 6,000 Dutch volunteers.

The colors were then digitally quantified and collated using high-resolution photographs of the whole eye, and the scientists found that human eye color varies in many more ways than previously thought.

Previous studies on the genetics of human eye color used broad trait information such as "blue," "green," and "brown," the researchers, led by Manfred Kayser, wrote in the study.

But this study showed that variation in eye color runs in a continuous grading from the lightest blue to the darkest brown.

"These findings are of relevance for future forensic applications where appearance prediction from biological material found at crime scenes may provide investigative leads to trace unknown persons," Kayser said.

Kayser's team pinpointed three new genes which they said were "significantly associated" with quantitative eye color.

Together with previously identified ones, these three genes could explain more than 50 percent of eye color variance, they said -- the highest accuracy so far achieved in using genes to predict a complex human trait.

The study was published in the Public Library of Science (PLoS) Genetics journal on Thursday and is available here: here:doi/10.1371/journal.pgen.1000934